Pump piston



@c%. 1?, 150 J. c. FRANCIS, JR 5 9 PUMP PISTON Filed Dec. 20, 1947 \JAMES C. FQAM c1 S J INVENTQR.

ATTOENEY Patented Oct. 17, 1 950 2,526,465 PUMP PISTON .James C.Francis, J12, Fort Worth, Tex., assignor to Superior Oil ToolCorporation, Dallas, Tex., a corporation of Texas Application December20, 1947, Serial No. 792,908 4 Claims. (01. 309 -4) This inventionrelates to pistons for slush pumps, and the like, of the type ordinarilyemployed in oil well drilling operations for pumping and circulatingdrilling fluids, and its principal object resides in the provision of adurable and economical piston in which is embodied certain novelfeatures of construction by which the piston rubbers, of the cup type,can be quickly and easily installed at the job, resulting in greatsavings of time and labor costs.

Another object of the invention resides in the provision of a slush pumppiston which is comprised primarily of metal for its supportingstructure, yet providing an assembly which is capable of affording themaximum of efficiency in operation, effecting a minimum of wear on thecylinder liner while providing exceptional flexibility in performance tolighten the load and, at once, increase the volumeof the pump in whichit is installed.

Still another object of the invention resides in the provision of apiston structure having a body portion of durable metal to which thepiston rubbers can be attached with economy and replaced, as the sameare worn due to abrasive substances in the fluids handled by the pump,and providing a device in which a minimum amount of rubber, or othersuitable composition, need be employed, resulting in longer life for thepiston liner, less slippage in operation and greater economy ininstallation and replacement.

Broadly, the invention contemplates the provision of a slush pump pistonwhich is light and economical in construction, highly efficient inoperation and capable of being quickl installed with a minimum loss oftime; and further contemplates the provision of a piston which isinterchangeable with practically all of the standard brands of slushpumps now inuse.

While the foregoing objects are paramount, other and lesser objects willbecome manifest as the description proceeds, taken in connection withthe appended drawings wherein:

Figure 1 is a vertical cross-sectional View of the piston structure,illustrating the form of the body and the interlocking rubber cup,the-assembly being shown attached to a tapered pump rod of conventionaldesign.

' Figure 2 is a lateral cross-sectional View of the piston, taken onlines 2-2 of Figure 1, illustrating the arrangement of integralinterlocking lugs formed on the rubbers engageable with the piston body.

Figure 3 is a perspective illustration of the body of the piston,showing the plurality of staggeredly :';rods having straight spindles.

arranged slots for receiving the interlocking lugs on the cup members,and

Figure 4 is an elevational view of the inner side of the rubber cupmembers, showing the staggered arrangement of integral lugs formedthereon providing interlocking association of the cup members with thepiston body.

Accordingly, the invention comprises a main body portion It which isformed with a substan- -;tially cylindrical hub ll whose inner bore [2is preferably tapered, as in Figure 1, and thus adapted to be applied tothe conventional tapered spindles of pump rods i3 which are generallydeemed stronger and capable of longer life than About the central hub IIthe body is formed with a hollow, drumlike structure [4, integral withthe hub II, and about its periphery is formed an integral flange [5whose opposite faces a are tapered inwardly, as in Figure l. V

The opposite faces it of the hollow portion E4 of the body Ill, are eachformed with a plurality of staggeredly arranged arcuate slots H whichextend through the walls of the member M, as illustrated in Figures 1and 3. It is desirable that the portion IA of the body II! have itsopposite faces [6 at right angles to the axis of the hub II. However, itis obvious that the faces It may be inclined either inwardly oroutwardly, as desired, but the piston thrust can be better absorbed'bythe right angular arrangement of the faces I6 which support the cuprubbers l8, illustrated in Figures 1 and 4, fitted thereagainst.

The rubbers I8 are disk-like in form, as shown in Figure 4, and haveannular flanges l9 formed thereon whose outer rims b are bevelledinwardly, as in Figure 1, conformable to the inwardly tapered faces a ofthe flange 15. The annular flanges l9 have their outer surfaces slightlyinclined toward their tips 1) and, with a slightly bevelled annularsurface 20 formed on the outer edges of their faces, the rubbers l8 areformed with peripherallips 2| about their peripheries which are adaptedto expand against the pump liner under pressure of the fluid.

The inner faces of the rubbers l8, as depicted in Figure 4, are formedwith a staggered arrangement of integral, arcuately formed lugs 22 whichare engageable with the arrangement of arcuate slots 11 in the face ofthe drum-like portion I4 of the body ID, as illustrated in Figure 1.Such an arrangement will prevent any rotative movement of the rubbers ISon the body Ill and serve to provide a more rigid and compact structurefor the entire piston assembly.

The rubbers 18 are retained upon the body by retainer plates 23, whichare disk-like in form, and secured by cap screws 24 extending throughthe rubbers l8 and threaded into the opposite faces 16 of the drum-likeportion I4 of the body 10, as illustrated in Figure l. The provision ofthe hollow space 24' within the portion [4 of the body l0 lightens thepiston assembly and affords greater efficiency in the operation of thepump. The hub H of the body in is arranged over the tapered spindle 25of the pump rod 13 and is secured by a nut 26 threaded upon the outerend of the spindle 25, in the conventional manner. A packing ring 2! isprovided to eifect a fluid-tight seal about the spindle 25 and reposesin an annular recess 0 in the end of the hub II. The nut 26 bearsagainst a washer 28 which retains the ring 27 in the manner shown inFigure 1.

The cup rubbers [8 are identical in form and are interchangeable so thateither can be applied to the body I!) from either side thereof and suchan arrangement provides for greater economy in stocking as well ashandling the members IS. The body l0 may be formed by casting the samein any suitable metal, such as brass, steel, or the like, a minimum ofmachining being required to adaptthe body I {I for installation and theattachment of the rubbers l8.

Manifestly, the structure herein shown and described is capable ofconsiderable modification, from time to time, by persons skilled in theart, without departing from the spirit and intent of the invention orthe scope of the appended claims.

What is claimed is:

1. In a piston for slush pumps, and the like, in combination with aplunger rod and pump liner, a cast body member having a hollowcylindrical, drum-like form, and an integral hub portion comformable tosaid plunger rod, the said body member having each of its opposing facesspaced inwardly from the ends of said hub portion and formed with aplurality of spaced slots, an integral flange formed intermediate theends and about the periphery of said body member, a pair of flexible cupmembers interchangeably arranged over said body member and havingintegral bosses on their inner faces adapted to engage said slots, andretainer plates for said cup members.

2. In a slush pump piston, in combination with a pump rod and cylinderliner, a hollow body formed with a hub member conformable with said pumprod, said body having opposing faces spaced inwardly from the ends ofsaid hub member, an integral flange arranged about the periphery of saidbody, a pair of cup members opposingly arranged on said body and havinginterlocking means thereon detachably associating the same with saidbody member, and retainer plates securing said cup members on said bodymember.

3. In a slush pump piston, in combination with a pump rod and cylinderliner, a hollow body member formed with a hub portion adapted to fitsaid pump rod, the said body member being cylindrical in form and havingopposing faces transversely of its axis and spaced from the ends of saidhub member, a peripheral flange formed about said body intermediate itssaid faces, a staggered arrangement of slots formed in each of saidfaces, a pair of identical pump rubbers arranged over said body andjoining said flange, and having detachable interlocking association withthe said slots, and retainer means removably securing said pump rubbers.

4. In a slush pump piston, in combination with a pump rod and cylinderliner, a body portion formed with a hub member conformable to said rod,the said hub member extending from each side of said body memberproviding seats for flexible cup members operating in said liner, a-

pair of identical cup members arranged in opposing relationship aboutsaid body portion and having detachable interlocking associationtherewith, and means retaining said cup members in position on said bodymember.

JAMES C. FRANCIS, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,770,123 Bettis July 8, 19301,949,612 Mattair et al Mar. 6, 1934 1,983,780 Shimer Dec. 11, 19342,287,483 Miller June 23, 1942' 2,443,110 MacClatchie June 8, 1948

